Complete the human trait inventory Warm up

Wanna see something weird from our knowledge of genetics? Review of Genetics Wanna see something weird from our knowledge of genetics?

Knowledge of Genetics Replace This With This!

Eat your vaccine “Being edible, the vaccines require no syringes- which aside from costing something, can lead to infections if they become contaminated.” Scientific America v16 #4

Chromosome Explanation Inheritance $ $ $ $ $ $ $ Chromosome Explanation *

How can two brown rabbits have a white bunny How can two brown rabbits have a white bunny? (try to think genetically)

Law of Dominance An organism with a dominant allele for a particular trait will always exhibit that form of the trait.

Law of Dominance *

Homozygous Heterozygous RR rr Rr

Law of Segregation You will only pass on 1 of your two copies of a gene to the next generation. *

BY THE WAY… Phenotype Genotype *

Phenotype A phenotype is any observable characteristic or trait of an organism (Looks)

Genotype the actual genetic makeup of an organism (Letters)

Question Does the gene that determines whether a seed is round or wrinkled in shape have anything to do with the gene for seed color ?

Hmm… I don’t think so… I believe that they are separate Let’s see what Mendel did to find out

Law of Independent Assortment Mendel crossed pea plants looking specifically for 2 traits… *Round or wrinkled pea shape *Yellow or green pea color R r Y y

Law of Independent Assortment He crossed plants that he KNEW were heterozygous for these traits… What were the genotypes/Phenotypes for these plants?

Law of Independent Assortment R r Y y Genotype = Phenotype = Round and Yellow

Law of Independent Assortment So what did he find? 9 Round/Yellow 3 Round/green 3 wrinkled/Yellow 1 wrinkled/green

Law of Independent Assortment

Back to the Question So…does the gene that determines whether a seed is round or wrinkled in shape have anything to do with the gene for seed color ?

Law of Independent Assortment No!…Genes for different traits can segregate (“separate”) independently during the formation of gametes Watch, I’ll show you…press the cheese!

Summary of Mendel The inheritance of biological characteristics is determined by individual units known as genes. Genes are passed on from parents to their offspring. When two or more forms (a____) of the gene for a single trait exist, some forms may be dominant and others recessive. Each adult has two copies of each gene- one from each parent. These genes are segregated from each other when gametes (sex cells) are formed. The alleles for different genes usually separate independently of one another.

Cuidado… It’s definitely not always that simple!!

Beyond Dominant and Recessive Alleles can be trickier than wrastlin’ Gators mate!

Beyond Dominant and Recessive Croiky! He’s right! There’s things like Incomplete Dominance …Codominance… and more mate!

What’s he talking about What’s he talking about? I thought the alleles were either Dominant or recessive

Different kinds of Dominance Incomplete Dominance Codominance Multiple Alleles Polygenic traits

Incomplete Dominance In incomplete dominance, the heterozygous phenotype is somewhere in between the two homozygous phenotypes

How about an example?

Incomplete Dominance Some Flowers

Who lives in a Pineapple under the sea?

Now Lets look at Codominance

Codominance In this situation, both alleles contribute to the phenotype (physical characteristics). In other words, neither allele is dominant.

Codominance

Here’s an example using CHICKENS! Codominance Here’s an example using CHICKENS!

Both black & white feathers At the other extreme from complete dominance is codominance in which two alleles affect the phenotype in separate, distinguishable ways. X White Chicken Black Checkered Chicken Both black & white feathers

Multiple Alleles Allele Allele Allele Allele Allele Allele Allele Many genes have more than two alleles and are therefore said to have “multiple alleles” Allele Allele Allele Allele Allele Allele Allele Allele Allele Allele

Most genes have more than two alleles in a population. This does not mean that an individual can have more than two alleles!! It only means that more than two kinds of alleles exist in the entire population!

The ABO blood groups in humans are determined by three alleles, IA, IB, and i.

I I or I i A B I I A and B AB i i none O Both the IA and IB alleles are dominant to the i allele. Genotypes Surface Phenotypes Molecules I I or I i A A A A B B B B I I A B A and B AB i i none O

I I or I i A B I I A and B AB i i none O The IA and IB alleles are codominant to each other. Genotypes Surface Phenotypes Molecules I I or I i A A A A B B B B I I A B A and B AB i i none O

I I or I i A B I I A and B AB i i none O Genotypes Surface Phenotypes Because each individual carries two alleles, there are six possible genotypes and four possible blood types. Genotypes Surface Phenotypes Molecules I I or I i A A A A B B B B I I A B A and B AB i i none O

I I or I i A B I I A and B AB i i none O Genotypes Surface Phenotypes Individuals that are IA IA or IA i are type A and place type A oligosaccharides on the surface of their red blood cells. Genotypes Surface Phenotypes Molecules I I or I i A A A A B B B B I I A B A and B AB i i none O

I I or I i A B I I A and B AB i i none O Genotypes Surface Phenotypes Individuals that are IB IB or IB i are type B and place type B oligosaccharides on the surface of their red blood cells. Genotypes Surface Phenotypes Molecules I I or I i A A A A B B B B I I A B A and B AB i i none O

I I or I i A B I I A and B AB i i none O Genotypes Surface Phenotypes Individuals that are IA IB are type AB and place both type A and type B oligosaccharides on the surface of their red blood cells. Genotypes Surface Phenotypes Molecules I I or I i A A A A B B B B I I A B A and B AB i i none O

I I or I i A B I I A and B AB i i none O Genotypes Surface Phenotypes Individuals that are ii are type O and place neither oligosaccharide on the surface of their red blood cells. Genotypes Surface Phenotypes Molecules I I or I i A A A A B B B B I I A B A and B AB i i none O

Matching compatible blood groups is critical for blood transfusions because a person produces antibodies against foreign blood factors. *If the donor’s blood has an A or B oligosaccharide that is foreign to the recipient, antibodies in the recipient’s blood will bind to the foreign molecules, cause the donated blood cells to clump together, and can kill the recipient.

Universal recipient Universal donor

Phenotype depends on environment and genes. A single tree has leaves that vary in size, shape, and greenness, depending on exposure to wind and sun.

For humans, nutrition influences height, exercise alters build, sun-tanning darkens the skin, and experience improves performance on intelligence tests.

Even identical twins, genetic equals, accumulate phenotypic differences as a result of their unique experiences.

The relative importance of genes and the environment in influencing human characteristics is a very old and hotly contested debate.